Valve-gearing.



R. STAUB.

VALVE GEARING.

APPLICATION FILED MAY 23. 191.6.

, Patented M 7, 1917.

a s A Es PATENT OFFICE.

mmorr sTAUB, or wmrna'rm'm, swrrznnnm.

VALVE-Gamma.

i Specification of Letters fatent.

Application filed ma as, 1916. Serial m. 99,346.

To all whom it may concern Be it known that I, Ruoonr STAUB, a citizen of the Republic of Switzerland, residingat Winterthur, Friedensstrasse 1'6, Switzerland, have invented certain new and useful Improvements in Valve-Gearings; and I do hereby declare the following to be a full,

. may be used only a no-load valve'is opened.

Arrangements are lmown by means of which, upon the pressure in a hydraulic press reaching a certain maximum amount,

Some of these devices, however, after accomplishing a complete cycle of operations, have tobe returned into the starting position by hand, others.

that closes the no-load valve at the end of the baokward'stroke, the no-load valve acting atthe same time as distributing valve. Presses provided with a working piston and a lifting piston are,also known, which are automatically reversedon reaching a certain stroke. These presses do not, however, exert a satisfactory pressure onthe work and. frequently fail to act, as the work, by its reaction on the piston, will prevent the latter from reaching theposition necessary for the reversing, the safety valv'eshaving been opened by the-increased'hydraulic pressure inthepump.

There are further known valve gear de- .vices for multiple presses, which are directly connected to centrifugal pumps or to hydraulic accumulators and in which on reaching a certain pressure, the next higher pressure is admitted, until the final pressure is obtained. It is however necessary to reverse the press every time by hand, whereupon the distributing plun'gers return automatically .to the starting'positlon. All known arrangements of this kind refer to presses with one piston only. S I

f Theapplication of the.present invention to presses with one piston only would constitute an exception,'while as a rule the infor presses having a piston vention will be applied to presses having Patented'Aug. '7, 1917,

pair of pistons, that is working and lifting,

pistons. In the case of stone presses, presses for iron chips, or the like, the liftingpiston may be omitted, its over by the workin'g piston.

notion being taken A further disadvantage-of all known gear 1 valves for hydraulic presses is that the re versaltakes place'while the liquid is still under pressure from t e pump, whereas it 1 would be desirable to operatethe distributmg valves only after the hydraulic pressure hasceased to act on them According to the present invention, the valve gear system of the pump is actuated by mechanical means and the described disadvantages are obviated, as the pressure gov- .erning piston, .1n raisingothe weight of. the

a pressure governor, opens .the no-load valve by means of a tipping device and at the same time by means of a free-Wheel mechanism allows the governing or cam shaft to remain in its initial position, while upon a down-' ward movement of the pressure piston and of the weight of the pressure jgovernor, the no-load valve is closed, this being,

overning however, only efi'ected after said cam shaft has been turned sufliciently for reversing the press from up to down strokeor'vice versa.

In this manner the hydraulic pressure is automatically brought toaot alternatively upon the working and the lifting cylinders.

Thus the cam shaft and with it the 'distributing valves are actuated fully automatically, upon the working pressure reaching a certain amount, and at a time, when saidvalves are not subjected to the full'pressure. "One form of carrying the invention into effect is shown by way of example in the ac-- companying drawing, in which- Figure -1 shows diagr'a atically the, manner of operation of the va ve gear;

Fig. 2 shows a front view and v Fig. 3 a side View of the hydraulic press, provided-)With the new valve gear;

2 and Fig. 5 a section on the line of Fig. 2. 105.

By a pump not shown in Fig. 1, water is Fig.4 is a section on the line A-B of Fig.

pressed through a'plpe 2 into a cylinder, 1 p

.which a pressure governing piston is movable. This piston 1s linked to'a rod 3 whicli actuates the ratchet lever 4', the ratchet wheel 4 being keyed upon a cam shaft 5 arranged to actuate the different distributing valves of a hydraulic press. The rod 3 is also linked to a lever 6 pivoted at 7 and carrying at one end a weight 8 while its other end is vconnected to a bell crank lever 10, by means of the connecting rod 9. This lever 10 is pivoted at 11 and actuates a slid ing rod 12 ending in a frame 13 which is adapted to operate thelower end of a lever 15 pivoted at 14 andcarrying on its other end a weight 16. Td. this lever 15 is linked a rod 17 carryinga slide 18 which works against a roller 20 of a cam disk 20 pivoted at 19 and having two cams 20 and 20 to engage a roller 21, which latter is arranged at one extremity of a valve stem 22 that actuates a valve 23. This valve 23 is connected to the delivery side of the pump 33 by means of a tube 24 and by means of a tube 25 it communicates with a water tank 32 from which pump 33 is fed.

The hydraulic press shown in Fig. 2 has a working piston 26, a lifting piston 27, one

pair of cam disks 28 for governing the flow of Water to or from the working piston 26 and one pair of cam disks 29 for governing the flow of water to or fromthe lifting piston 27. The curved cam slots in the two pairs of disks are identical in size and shape, but the two pairs of disks are so keyed upon the shaft 5 as to have the slots on the disks 28 turned for an angle of 60 in relation to the slots in the pair of disks 29.

As apparent from Figs. 4c and 5, the slots in the pairs of disks are so shaped and arranged relatively to each other, that, if the two valve pistons 34 and 35 actuated each by the corresponding pair of disks are in their highest and lowest position respectively, it will be sufficient to turn the cam shaft for an angle of 60 in order to reverse the relative positions of the said valve pistons.

If valve piston 34 is in its highest and valve piston 35 in its lowest position, pressure is admitted under piston 27 while the working cylinder communicates with tank' 32 and the press is being raised. If, on the other hand, valve piston 35 is in its highest, and valve piston 34 in its lowest position, then-pressure is applied to the working piston 26, and while the press accomplishes its downward stroke, the lifting piston 27 pushes water back into tank 32.

' .Working piston and lifting piston are connected to each other by means of screwthreaded rods 30 carrying adjusting nuts 31and 31'.

In the position shown, the working piston 26 is under pressure and will continue to descend, together with the lifting piston 27, until stopped by the nuts 31 striking the frame of the press. At once, the pressure in the working cylinder will rise until by raising the pressure governing piston in cylinder 1, valve 23 is opened and the conveying side of pump 33 connected with tank 32, so that the pump runs light and the hydraulic pressure sinks to zero. This valve 23 is now opened in the following'manner.

The excess pressure in cylinder 1 causes lever 6 and weight 8 to rise and ratchet lever 4, to turn, while the ratchet wheel 4 and cam shaft 5 remain in their position. Simultaneously, rod 12 is pushed to the right, so that the weight 16 travels from position III to position II, and II being a point of unstable balance, the lever will tilt over and theyveight arrive in position I. At the moment, when weight 16 is in its position II and begins its tiltin movement toward I, the weight 8 is in its ighest position and the slide 18 touches from the right hand side the roller 20' of cam disk 20. In tilting over into position I, the weight 16 carries the slide 18 along, cam disk 20 is turned, roller 21 lifted by cam 20' and the valve stem 22 is lifted, thereby opening valve 23.

From thismoment onward, the pump 33 runs idle and pressure in the working cylinder is reduced to a very small amount. Simultaneously, however, the pressure in the cylinder 1' decreases, the weight 8 falls carrying -with it rod 3, thereby turning the ratchet lever 4 which engages the ratchet wheel'4 and turns the cam shaft 5. The latter actuates the cam disks 28 and 29, whereby the press is reversed, but as the valve 23 is still open, the reversal takes place at no-pressure. As the weight 8 sinks to its lowest position, the frame 13 pushes the weight 16 from position I to position II, whence it tilts over, by gravity, to position III, so that cam disk 20 is returned to its first position. Roller 21 is lowered and the valve 23 thus automatically closed.

Now the pump 33 presses water under the lifting piston 27, and as the working cylinder communicates with the tank 32, the working piston 26 is raised until the lower nuts 31' by striking the frame, limit the lifting stroke. At once, the pressure in the cylinder of. the lifting piston 27 increases until the pressure is reached. that is necessary for actuating the valve gear and which is determined by the weight 8 and its position on the lever 6, when the reversal takes place once more as described.-

Instead of the 1 weight 16, some other mechanism embodying a spring might of course be em loyed, such as are used in machine tools, or instance. According to the present invention, the described valve gear maybe applied to hydraulic presses other than the one shown on the drawings as for instance to automatic five-cylinder concrete presses or in general to presses having an unlimited number of cylinders. It is clear, that the above described valve gear may also be used in connection with any other reciprocating machine driven by hydraulic means.

Having now particularly described and and effecting durin 'cycle an opening 0 the check-member arascertained the nature of the said inventionand in what manner the same is to be performed, I declare that what I claim is:

1. In combination, a cylinder, a piston working in the latter, a returning piston operatively connected with the first mentioned. piston, a cylinder for the returning piston, a pump, means connecting the pump to said cylinder, valves controlling the flow of the hydraulic means delivered by the pump through 'said "connecting means, means actuating said valves and a pressure controlling device connected to the delivery part of the pump and causing during a part -of its working cycle an interruption of the pump action upon the first mentioned iston and causing during the other part 0 said cycle at first a movement of the valves, which is adapted to effect a reversal of the machine, and afterward a renewed action of the pump upon said returning piston, substantially as described.

, 2. In combination, a working cylinder, a piston arranged'in the latter, a returning piston operatively connected to said first. mentioned piston, a cylinder for the returningpiston, a pump, means connecting the latter to said working cylinder and. the cylinder for the returning piston, valves controlling the flow of the medium delivered by the pump through said connecting means, means to actuate said valves, a by-pass con--.

necting the delivery part of the pump to its suction part, a check-member arranged in this by-pass, a pressure regulating device connected to the delivery part of the pump a part of its working ranged in'the by-pass and causing during the other part of its working cycle at first a movement of said regulating device effecting a reversal of the machineand afterward a closing ofthe check-member, so that I the hydraulic means driving the machine 1s brought to act alternatively upon the piston of the working cylinder and the returning. piston, substantially as described.v

3. .In combination, a working cylinder,

a piston arranged in the latter, a returning piston operatively connected to. said firstmentioned piston, a cylinder for the returning piston, a pump, meansconnecting the latter to said working cylinder and the cylinder .for the returning piston, valves con-. trolling the flow of the medium delivered by the pump through said connecting means, means to actuate said valves, a by-pass connecting the delivery part of the pump to its suction part, a valve arranged in this bypass,'an auxiliary cylinder connected to the delivery part and suction part of the pump, a piston working in this auxiliary cylinder, means operatively connecting thls pistonto the first mentioned valves and the valve arranged in the by-pass, the piston in said auxiliary cylinder being adapted to effect during one of its strokes an interruption of working cylinder and during the immediately following stroke at first a movement of the first mentioned valves, which effects a reversal of the movement of the machine,

' the pump action upon the piston in said and afterward a closing of the valve in the V I by-pass, so that the hydraulic means are brought to act upon the returning piston. substantially as described.

4. In combination, a working cylinder, a

piston arranged in the latter, a returmng' piston operatively connected to said first mentioned piston, a cylinder for the returning piston, a pump, means connecting the latter to said working cylinder and the cylinder for the returning piston, valves controlling the flow of the medium delivered by the pump through said connecting means, a cam shaft acting upon said valves, a ratchet wheel mounted on this shaft, a by-passconnecting the delivery part of the pump to its suction part, a valve arrangedln this bypass, an auxiliary cylinder connected to the the by-pass, the plston arranged in the auxiliary cylinder causing during its upward movement by means of the link and lever system, the tilting system and the cam disk an opening of the Valve in the by-pass, and during its downward movement at first a rotation of said cam shaft, which movement closes the connection between working cylinder and delivery part. of the pump and opens the connection. between this pump part and the cylinder for the reversing piston, and afterward by means of'the link and lever system, thetilting system and thecam disk a closing of the valve in the by-pass, so that the medium deliveredby the pump is brought to act upon said returning piston to effect the return stroke of the machine, substantially as described. I

5. In combination, a working cylinder, a piston arranged in the latter, a returning piston operatively connected to said first mentioned piston, a cylinder forthe returning piston, a pump, means connecting the latter to said working cylinder and the cyl inder for the returnlng piston, valves con- 90 delivery and suction parts of the pump, a v

trolling the flow of the medium delivered by the pump through said connecting means, a

cam shaft acting upon said valves, a ratchet,

its suction part, a valve arranged in the bypass, an auxiliary cylinder connected to the delivery and suction parts of the pump, a

piston working in the auxiliary cylinder, a rod connected to last named piston, a member fixed to the rod, a pawl carried by said member operatively connected to said ratchet wheel, a lever operatively connected to said larged end having a slot, a pivotally mountthe no-load valve is open.

ed lever provided at one of its ends with a weight and extending with its other end into the slotted end of said rod, a rod connected to this last mentioned lever and provided with a recess and a cam disk acting upon the valve arranged in the by-pass and provided wit aroll-shaped end lying in said recess, substantially as described.

. 6. In a valve gear for hydraulic presses directly connected to a pump, in combination, a pressure regulating piston, a no-load valve, valve-pistons controlling the distribution of the medium delivered by the pump, means for actuating said pressure regulating piston during each'stroke of the press, means operatively connected to said piston for actuating said no-l oad valve and means operatively connected to the pressure regulating piston for actuating said valve-pistons while 7. In a valve gear for hydraulic presses directly connected to a pump, in combination, a pressure regulating piston, a no-load valve, valve-pistons controlling the distribution of the medium delivered by the pump, means operatively connected to said pressure regulating piston for opening the no-load valve, cam disks for operating said valvepistons, a shaft carrying these disks and means operatively connected tothe pressure regulating piston. for rotating this shaft, while the no-load valve is open, to an amount, which is suflicient for eflecting the reversal of the press.

8. In a valve gear for hydraulic presses directly connected to a pump, in combination, a pressure regulating piston, a no-load valve, valve-pistons controlling the distribution of the medium delivered by the pump, means for actuating the pressure regulating piston during each stroke of the press, means operatively connected to the pressure regulating piston for actuating the no-load valve and a pawl and ratchet wheel mechanism operatively connected to said pressure regulating piston and to said valve-pistons.

9. In a valve gear for hydraulic presses directly connected to a pump, in combination, a pressure regulating piston, a no-load valve, valve-pistons controllingthe distribution o'f the medium delivered by the pump, means for actuating the pressure regulating piston during each stroke of the press, means comprising a tilting device operatively connected to said pressure regulating piston and a cam disk for actuating the no-load valve, and a pawl and ratchet wheel mechanism operatively connected to said pressure regulating piston and effecting, while the no-load valve is open, a movement of said valve-pistons causing a reversal of the press.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

RUDOLF STAUB. Witnesses:

CARL Gunman, ARNOLD LEHNER. 

